This invention relates to a process and catalyst for the dimerization of olefins to produce longer chained olefin products. In a further aspect, the invention relates to the production of olefins and alkylbenzenes which are especially useful as intermediates in the production of alkylbenzene sulfonate detergents. The invention also relates to such detergents and their production.
One significant commercial application of longer chained olefins (e.g., C.sub.10 to C.sub.28) is as intermediates in the production of alkyl aromatic sulfonate detergents. Since large amounts of such detergents are ultimately released to the environment, the need for biodegradability is well recognized. It is further well recognized that linear and mono-branched alkyl aromatic sulfonates are generally much more readily biodegraded than multibranched alkyl aromatic sulfonates and, hence, much more desirable as detergents. Thus, the need exists for processes which efficiently produce high yields of C.sub.10 to C.sub.28 linear and/or mono-branched olefins or olefin mixtures which afford biodegradable alkylbenzene sulfonates.
U.S. Pat. No. 3,315,009, issued Apr. 18, 1967 to Engelbrecht et al., discloses a two-dimerization step process for preparing C.sub.8 to C.sub.16 olefins using a heterogeneous cobalt oxide catalyst. Patentee teaches that it is preferred that the dimer feed to the second stage dimerization be substantially linear, but that the presence of branched-chain mono-olefins in the feed to the second stage up to 15% by weight is not deleterious.
U.S. Pat. No. 3,317,628, issued May 2, 1967 to Schuck et al., discloses a two-dimerization step process for preparing higher olefins similar to that described in the aforementioned U.S. Pat. No. 3,315,009, but using a somewhat different heterogeneous cobalt catalyst. Patentee stresses one of the advantages of patentee's process is that the formation of undesired isomers, such as 2-methylpent-2-ene is minimized if not eliminated. Patentee describes 2-methylpent-2-ene as an especially undesirable isomer in hexene fractions for the purpose of patentee's process because it is not separated from n-hexene by commercial methods of distillation and therefore requires special separation procedures or it must remain as an impurity.
U.S. Pat. No. 3,402,217, issued Sept. 17, 1968 to EngeIbrecht et al., discloses a two zone polymerization process for preparing higher olefins using a molecular sieve or zeolite catalyst. Patentee teaches that a particularly preferred mono-olefin dimer feed to the second zone polymerization is one which contains no greater than 10% by weight of branched-chain mono-olefins and the remainder straight-chain mono-olefins. Patentee further teaches that generally ordinary fractional distillation is adequate to purify the first dimerization zone product, but that in addition to or in place of fractional distillation, other conventional separation or purification means such as adsorbents, i.e., molecular sieves, solvent extraction, extractive distillation, selective polymerization, isomerization, and the like may be employed to conform the dimer product of the first-stage dimerization to the feed requirements of the second-stage dimerization. Patentee states that it is immaterial to patentee's invention what separation means is used for purifying the product of the first-stage dimerization to meet the feed requirements of the second-stage dimerization, so long as such separation means provides the desired purification.
U.S. Pat. No. 3,409,703, issued Nov. 5, 1968 to Engelbrecht et al., discloses a two-dimerization step process similar to that disclosed in U.S. Pat. No. 3,315,009, but using a modifying agent in the first dimerization.
U.S. Pat. No. 3,424,815, issued Jan. 28, 1969 to Cannell et al., describes the preparation of .alpha.-olefin oligomers using a catalyst comprising the product of certain nickel chelates with a halide-free organo-aluminum compound such as alkyl aluminum alkoxides. Patentee teaches that the nickel chelating ligand-anion is substituted with electron withdrawing groups, i.e., nitro, halo, cyano or carboalkoxy and that superior results are obtained when the chelating ligands are halogenated organic ligands.
U.S. Pat. No. 3,592,870, issued Jul. 13, 1971 to Dunn, discloses an olefin dimerization process using a catalyst formed from an organoaluminum compound and one of the following nickel complexes: (a) bis(.beta.-mercaptoethylamine)nickel (II) complex; (b) .alpha.-diketobis(.beta.-mercaptoethylimine)nickel (II) complex; (c) S,S,-disubstituted bis(.beta.-mercaptoethylamine)nickel (II) complex; or (d) S,S, -disubstituted-.alpha.-diketone bis(.beta.-mercaptoethylimine)nickel (II) complex. Based on the product distribution shown in the examples of this patent, the dimerization of propylene using patentee's catalysts resulted in C.sub.6 olefin products containing 63 to 70% branched olefins depending on the particular catalyst used.
U.S. Pat. No. 3,910,869, issued Oct. 7, 1975 to Throckmorton, discloses a process for the polymerization of butadiene and butadiene in mixture with other diolefins to form polymers containing a high proportion of butadiene units in the cis-1,4 configuration. The process involves contacting the monomer under solution polymerization conditions at temperatures ranging from -10.degree. C. to 100.degree. C. with a catalyst containing an organoaluminum compound, an organonickel compound and hydrogen fluoride.
U.S. Pat. No. 4,069,273, issued Jan. 17, 1978 to Komoto, describes a process for dimerizing low molecular weight linear .alpha.-olefins using a complex of bis(1,5-cyclooctadiene)nickel and hexafluoro-2,4-pentanedione as a homogeneous catalyst. Patentee describes his process as producing a highly linear olefin product. U.S. Pat. No. 4,366,087, issued Dec. 28, 1982 to Le Pennec et al., describes a process for oligomerizing olefins using a catalyst containing a hydrocarbyl aluminum halide and a nickel compound having the formula (R.sub.1 COO)(R.sub.2 COO)Ni, wherein R.sub.1 is a hydrocarbyl radical having at least 5 carbon atoms and R.sub.2 is a haloalkyl radical. As can be seen from the examples in this patent, patentee's process afforded a product containing a large amount of branched olefins. A number of catalyst systems used for the polymerization of olefins are described in Chemical Review, 86 (1986), pp. 353-399.
U.S. Pat. No. 4,102,817, issued Jul. 25, 1978 to Throckmorton et al., discloses a process for producing cis-1,4 polybutadiene by contacting butadiene with a catalyst consisting of (1) at least one organoaluminum compound, (2) at least one nickel compound, selected from nickel salts of carboxylic acids, organic complex compounds of nickel and nickel tetracarbonyl, and (3) at least one hydrogen fluoride complex prepared by complexing hydrogen fluoride with a ketone, ester, ether, alcohol, nitrile or water.
U.S. Pat. No. 4,187,197, issued Feb. 5, 1980 to Kabanov et al., discloses a method for dimerizing C.sub.2 to C.sub.4 olefins using a two component catalyst containing (1) a complex of a nickel salt with a tertiary phosphine or tertiary phosphite and (2) an organoaluminum compound which is a rubber selected from natural and synthetic carbo-chain rubber with a content of 2 to 50 mol % of Al Rx units wherein R is an alkyl with at most 8 carbon atoms and x is a halogen, the atomic ratio of Al/Ni being from 1:1 to 100:1.
U.S. Pat. No. 4,404,415, issued Sept. 13, 1983 to Gaillard, discloses a process for producing nonenes and dodecenes from propene. The repeated addition of propene to recycled hexene and nonene reaction products is catalyzed by a catalyst substantially similar to that disclosed in U.S. Pat. No. 4,366,087.
U.S. Pat. No. 4,677,241, issued Jun. 30, 1987 to Threlkel, discloses a process for the oligomerization of a lower olefin having 2 to 8 carbon atoms by contacting the lower olefin with a catalyst containing a transition metal complex selected from complexes of nickel and palladium with a fluoro-organic thiol or sulfide ligand, having a single sulfur atom in a ligating position and wherein the carbon atoms adjacent the carbon to which the sulfur atom is attached has at least one fluoro substituent and with the proviso that the fluoro-organic thiol or sulfide does not contain any other ligating group or atom in a ligating position which will displace the fluoro as a ligand, and an organometallic-reducing agent selected from borohydride and organoaluminum halides and hydroxides.
Although the prior art speaks of highly linear products, seldom are such results obtained except at the cost of low yields or other disadvantages. For example, the two-step processes of the prior art which produce highly linear C.sub.10 to C.sub.15 olefin products also generally require a highly linear intermediate product, thus effectively wasting significant yields of methyl pentenes which are obtained in the first step reaction product. The prior art systems using heterogeneous catalysts suffer from the usual contact problems incident to such catalysts. Moreover, the heterogeneous catalysts used by the prior art are frequently difficult and expensive to prepare. The use of halide modifying agents also presents a problem since such agents are generally very corrosive and presents equipment problems.
One of the principal uses of C.sub.10 to C.sub.28 olefins is as intermediates for detergents and lube oil additives, e.g., sulfonated alkyl benzenes. When used for detergents, the C.sub.10 to C.sub.28 olefin product should have a high proportion of linear or mono-branched olefins because detergents produced from predominantly linear olefins are generally more readily biodegraded than those produced from highly branched olefins. Similarly, mono-branched olefins are generally more readily biodegraded than multi-branched olefins and, accordingly, more desirable for detergents. When used as an intermediate for lube oil additives, the C.sub.10 to C.sub.28 olefin product should have a high proportion of mono-branched olefins because lube oil additives produced from mainly mono-branched olefins have premium properties such as low pour points or melting points compared to either linear or multi-branched olefins.
Thus, there exists a need for detergent grade C.sub.10 to C.sub.28 linear and mono-branched olefins and, accordingly, there exists a need for better processes for preparing detergent grade C.sub.10 to C.sub.28 linear and mono-branched olefins.